Genealogy is the study of the history of families and the line of descent from ancestors. It is an interesting subject studied by many professionals as well as hobbyists. Traditional genealogical study techniques typically involve constructing family trees based on surnames and historical records. As gene sequencing technology becomes more accessible, there has been growing interest in genetic ancestry testing in recent years.
Existing genetic ancestry testing techniques are typically based on deoxyribonucleic acid (DNA) information of the Y chromosome (Y-DNA) or DNA information of the mitochondria (mtDNA). Aside from a small amount of mutation, the Y-DNA is passed down unchanged from father to son and therefore is useful for testing patrilineal ancestry of a man. The mtDNA is passed down mostly unchanged from mother to children and therefore is useful for testing a person's matrilineal ancestry. These techniques are found to be effective for identifying individuals that are related many generations ago (e.g., 10 generations or more), but are typically less effective for identifying closer relationships.
Genealogy researchers are often interested in learning whether a relative of a person is a patrilineal relative (i.e., a relative on the person's father's side) or a matrilineal relative (i.e., a relative on the person's mother's side). Existing personal genetics services, however, typically do not provide such information since the information can be difficult to ascertain on the basis of just the genetic information of the person and the relative.